The quantitative determination of analytes in body fluids is of great importance in the diagnoses and maintenance of certain physiological abnormalities. For example, lactate, cholesterol, and bilirubin should be monitored in certain individuals. In particular, determining glucose in body fluids is important to diabetic individuals who must frequently check the glucose level in their body fluids to regulate the glucose intake in their diets. The results of such tests may be used to determine what, if any, insulin and/or other medication needs to be administered. In one type of testing system, test sensors are used to test a fluid such as a sample of blood.
One method of monitoring an individual's blood glucose level is with a portable, hand-held blood glucose testing device (e.g., a meter). To determine the blood glucose level with the meter, a lancet device may be used with a needle lancet that pierces the skin tissue and allows a whole blood sample to form on the skin's surface. Once the requisite amount of blood forms on the skin's surface, the blood sample is transferred to a test sensor. The test sensor is generally placed in an opening in the body of the meter.
Test-sensor cartridges are commonly used to individually dispense test sensors to be used for testing an analyte in a fluid. The cartridges are used to store multiple sensors and allow users to carry multiple sensors around within a single enclosure. During testing, a blood or body fluid sample may be placed on the sensor and analyzed with the meter or instrument to determine the concentration of the analyte being examined.
The test-sensor cartridges may be incorporated directly into, for example, glucose meters to dispense test sensors for use with the meter. The cartridges may include features designed to mate with corresponding features inside of a meter to assist in indexing and/or excising the test sensors located within the cartridges. Alternatively, the cartridges may be kept separate from the meter. In such embodiments, a user may remove a single sensor from the cartridge to perform an analyte test. The cartridges assist in preventing or inhibiting test sensors from being exposed to the environment until they are required for use. Exposure to the environment (e.g., humidity, contaminants, or the like) may damage the test sensors, thereby altering test results.
Because different types of test sensors or test-sensor versions may have significant differences associated therewith, a problem occurs when a test sensor is used with a meter that was not designed to be used with the test sensor. This may occur, for example, when a user tests with a test sensor being placed into a meter that is not compatible with the test sensor. Alternatively, problems may occur if a meter is unable to distinguish the type and/or generation of test sensor being used or the calibration information associated therewith. Different types of test sensors may include different types of sensor reagent, which may influence items such as, for example, the amount of fluid sample needed and the length of time required for the reagent to react with the analyte to determine the analyte concentration. Furthermore, different test sensors may correspond with different assay parameters, protocols, and/or programs including test sequences, test times, algorithms, voltage, calibration information, expiration dates, or the like.
Many existing meters require that a user perform some affirmative act to notify the meter that a new test-sensor cartridge is being used so that the meter may calibrate and/or modify its testing parameters, protocols, and/or programs accordingly. For example, the user may be required to remove a code chip corresponding with the previously used cartridge and replace it with a code chip corresponding with a new cartridge. Oftentimes, however, the user minimizes the importance of performing such a notification step and/or forgets to change the code chip. Users may view this step as being optional and, in the interest of time, choose to skip the step altogether. Furthermore, because testing may be performed without notifying the meter of the type of cartridge and/or test sensors being used, it is relatively easy for a user to overlook performing this step.
Because meters are generally designed to perform protocols and run programs associated with certain test sensors, mismatching test-sensor cartridges and meters generally yields inaccurate test results. Inaccurate test results may result in dangerous analyte levels (e.g., hyperglycemic or hypoglycemic conditions) being undetected, which may be dangerous for a user and may have serious health-related consequences. At a minimum, mismatching test-sensor cartridges and meters may require extra testing, which may be inconvenient and expensive for a user.
It would be desirable to provide analyte-testing instruments (e.g., test-sensor cartridges) that inhibit or prevent using a meter with unsuitable types and/or generations of test-sensor cartridges.